Bacteremia following dental implant surgery : preliminary results

Objectives: The aims of this study were to investigate the incidence of bacteremia, bacteriology and antibiotic susceptibility against to causative bacteria associated with dental implant installation. Study Design: 30 generally healthy patients were enrolled in this study. Blood samples were collected at baseline and at 30 minutes after dental implant installation and 24 hours after dental implant surgery. Blood samples were cultured in a BACTEC system. The isolated bacteria were identified using conventional methods. Antimicrobial sensitivity tests were performed by disc diffusion. Results: No bacteria were isolated at the baseline and 24 hours after surgery, whereas the prevalence of bacteremia at 30 minutes after dental implant installation was 23%. The isolated bacteria species were Staphylococcus epidermidis, Eubacterium spp., Corynebacterium spp. and Streptococcus viridans. The Staphylococcus epidermidis, which was isolated in three patients, was found to be resistant to penicillin which is first choice of many clinicians. Conclusion: Our findings suggest that installation of dental implants can produce bacteremia. Within the limitations of this study, it can be speculated that the resistance of antibiotics may compromise the routine prophylaxis against infective endocarditis. Therefore use of blood cultures and antibiograms may be suggested in risky patients. The outcome of the present study should be verified using a larger patient group with varying conditions. © Medicina Oral S. L

Anaerobic bacteria isolated from clinical specimens in a university hospital and resistance of anaerobic Gram negative rods to antibiotics

Objective: Although anaerobic bacteria are normal microbiota members in humans, they can cause endogenous and exogenous infections. The empirical treatment of anaerobic infections is based on reports of susceptibility patterns reported in various studies. This study aims to identify the anaerobic bacteria isolated from clinical samples in 2018 and to determine the resistance of anaerobic Gram negative rods to antibiotics and to compare the results obtained with the results of anaerobic Gram negative rods isolated between 2015 and 2017 in the same unit in this study.Material and method: Specimens were inoculated on Schaedler Agar and Cooked Meat Broth and incubated in anaerobic conditions. Bacteria were identified by colony morphologies, conventional tests and anaerobic diagnostic discs. Antibiotic susceptibility tests were performed using the concentration gradient method and evaluated according to the criteria of CLSI.Results: Of the 1,630 clinical samples sent for anaerobic culture, 41 (2.5%) anaerobic bacteria were isolated. Most of the bacteria were isolated from the Department of Gynecology and Obstetrics (29%), Otorhinolaryngology (29%) clinics and mostly abscess specimens (49%). Seventy-one percent of the isolated anaerobic bacteria were Gram negative and 29% Gram positive bacteria. The most frequently isolated anaerobic bacteria were Bacteroides fragilis group (24%) and Prevotella spp (22%). Clindamycin resistance was quite high and there was no carbapenem resistance in anaerobic Gram-negative rods, but one third of the isolates were resistant to amoxicillin+clavulanic acid. Conclusion: It was remarkable that more than half of the isolated anaerobic Gram negative rods, especially the B. fragilis group, were resistant to clindamycin and about a third of amoxicillin+ clavulanate. Increased resistance to these antibiotics used empirically in the treatment of infections caused by anaerobic Gram-negative rods is anticipated to limit antibiotic treatment regimens in the future. Routine monitoring of resistance is necessary for proper empirical treatment

SAĞLIK BİLİMLERİNDE KLİNİK MİKROBİYOLOJİ

Bu bölümün konusu olan patojen (insanda hastalık yapan) Gram pozitif bakteriler Staphylococcus, Streptococcus, Enterococcus, Bacillus, Corynebacterium, Listeria, ve Clostridium cinslerinde yer alırlar. Bunlardan Clostridium cinsi bakteriler“Anaeroblar, Spiroketler ve Diğer Patojen Bakteriler” başlığı altında ayrıca inceleneceğinden burada bahsedilmeyecekti

Klinik örneklerden izole edilen çoğul dirençli Acinetobacter baumannii suşlarinda kolistin, polimiksin b ve tigesiklinin invitro etkinliği

Amaç: Acinetobacter baumannii doğada yaygın olarak bulunmakta ve sert yüzeylerde uzun süre yaşamını sürdürebilmektedir. Farklı antibiyotik sınıflarına direnç kazanma yeteneğine sahip olup, bu özellik çoğul direnç olarak tanımlanır ve tedavi seçeneklerini kısıtlar. Son 10 yıldır çoğul dirençli A. baumannii (MDRAB) suşları artan şekilde bildirilmeye başlanmıştır. Bu çalışmada da, son dört yılda çeşitli klinik örneklerden izole edilen 75 MDRAB suşunun kolistin, polimiksin B ve tigesiklini kapsayan çeşitli antibiyotiklere in vitro aktiviteleri değerlendirilmiştir. Gereç ve Yöntem: Suşların tanımlanması otomatik sistemlerle yapılmıştır. Antibiyotik duyarlılık deneyleri kolistin, polimiksin B ve tigesiklin için Etest, diğer antibiyotikler için disk difüzyon yöntemiyle yapılmıştır. Tigesiklin için MİK değerlerini yorumlamada Food and Drugs Administration (FDA) kriterleri, diğer antibiyotikler için Clinical and Laboratory Standarts Institute (CLSI) kriterleri esas alınmıştır. Bulgular: Suşların tamamı MDRAB olarak tanımlanmış ve tamamı en az üç antibiyotik sınıfına dirençli, %95’i de en az bir karbapeneme dirençli olarak bulunmuştur. Tüm suşlar kolistin ve polimiksin B’ye duyarlı bulunmuştur. Suşların %60’ı ampisilin-sulbaktam, amikasin, imipenem üçlüsüne dirençli bulunmuştur. Suşların üçü imipenem ve meropenemden yalnızca birine duyarlı, dördü her ikisine de duyarlı ve kalanı (%91) ise her iki karbapeneme de dirençli bulunmuştur. Suşların 46’sı (%61) tigesikline duyarlı, 27’si (%36) orta duyarlı ve ikisi (%3) dirençli bulunmuştur. Karbapenemlere dirençli suşların %38’i tigesikline dirençli veya orta duyarlı bulunmuştur. Kolistin, polimiksin B ve tigesiklin için MİK50 ve MİK90 değerleri sırasıyla 0.19-0.50μg/ml; 0.38-0.50μg/ml; 2-3μg/ml olarak bulunmuştur. Sonuç: MDRAB suşlarında kolistin ve polimiksin B’nin, tigesikline göre daha iyi in vitro aktiviteye sahip olduğu saptanmıştır. Tigesikline direncin görülmeye başlanması, gelecekte direncin artacağı endişesini ortaya çıkarmaktadır

Detecting of colistin resistance via different methods in multi-drug resistant Gram-negative bacilli isolated from blood cultures

The isolation of colistin-resistant bacteria from bloodstream has increased for few years, causing therapy failure. It is recommended to use colistin in combination in infections caused by these bacteria. Broth microdiution method is the recommended as a standard method to detect colistin resistance. However this method could not be used in routin laboratories since it is labor-intensive and time consuming; therefore the requirement for new easy methods has emerged.In this study, susceptibility to colistin of MDR-GNB was studied by macrodilution, disc elution, commercial microdilution, rapid polymyxin NP tests and compared to broth microdiution to evaluate detecting of colistin resistance in MDR-GNB (n=102) isolated from blood cultures sent from different wards in 2019-2020. The combination of colistin with tigecycline and meropenem were then tested by checkerboard method. Additionally mcr-1 gene was investigated by PCR in colistin resistant isolates.Resistance to colistin was found to be 15%, MİK50 and MİK90 were found to be ≤0.25 μg/ml and 16 μg/ml by BMD method. The categorical agreement was very well (100%) in four methods no very major errors. However macrodilution and commerical microdilution (Diagonistics 8011) methods showed the highest minor errors rates amongst the four methods. The best essential agreement rate was detected by disc elution method. Colistin-meropenem combination exhibited 100% synergism and colistin-tigecycline 80%. No mcr-1 genes were detected in colistin resistant isolates. In conclusion, disc elution and HPNP which those newly developed methods for detecting resistance to colistin were the easiest, cheapest, most efficient and best performing methods, so they are convenient to use in routine laboratory. Colistin-meropenem combination is thought to be an excellent choice to treat bacteremia/sepsis caused by colistin-resistant bacteria

Detection of colistin resistance via four methods in multi-drug resistant gram negative rods isolated from blood cultures

Introduction: The broth microdilution (BMD) method recommended for the detection of colistin resistance is labor-intensive and time-consuming, and it is difficult to apply in routine laboratories.. Thus, various methods, such as disk elution, commercial microdilution and rapid polymyxin-NP tests have been developed for detection of colistin resistance. In this study, a total of 102 multi-resistant Gram-negative bacteria isolated from blood cultures were evaluated by four different methods to detection of colistin resistance, and compared with the reference method.Methodology: For the detection of the compatibility of these methods with the reference method, categorical and essential agreements, very major, major and minor error rates were determined. Colistin-tigecycline and colistin-meropenem combinations were investigated in colistin-resistant isolates.Results: Of the isolates, 15 (15%) [K. pneumoniae (n=12), A. baumannii (n=2), E. coli (n=1)] were resistant to colistin with reference BMD method. MIC50 and MIC90 values of all isolates were ≤0.25 μg/ml and 16 μg/ml, respectively. The categorical agreement rates were 100% for commercial microdilution, disk elution and RPNP test. The essential agreement rates of commercial microdilution, disk elution and broth macrodilution were 78.4%, 86.3% and 100%, respectively. Although there were no major errors in these methods, the macrodilution (12%) and commercial microdilution (20.6%) methods showed the most minor errors. Colistin-meropenem combination showed 100% synergistic effect, but colistin-tigecycline combination showed 80% synergistic effect and 20% indifference effect.Conclusions: Disk elution and RPNP tests are suitable for routine use because they are the most efficient, easiest, low-cost and good performance tests in detecting colistin resistance